Fig. 2

Overview of applied tDCS protocols. A Stimulation protocols for experiment A. Participants either received 20 min. of 2 mA tDCS with the anode on the primary motor cortex (A1), 20 min. of 2 mA tDCS with the cathode on the primary motor cortex (A2) or sham stimulation (A3). B Stimulation protocols for experiment B. Participants either received two blocks of 10 min. of 2 mA tDCS with the anode on the primary motor cortex (interstimulus interval [ISI] of 20 min.; B1), two blocks of 10 min. of 2 mA tDCS with the anode on the primary motor cortex, with 20 min. of 2 mA tDCS with reversed polarity in between (B2) or sham stimulation (B3). C Stimulation protocols for experiment C. Participants either received four blocks of 5 min. of 2 mA tDCS with the anode on the primary motor cortex (interstimulus interval [ISI] of 10 min.; C1), four blocks of 10 min. of 2 mA tDCS with the anode on the primary motor cortex with two blocks of 10 min. of 2 mA tDCS with reversed polarity in between (C2), or sham stimulation (C3)